全文获取类型
收费全文 | 3948篇 |
免费 | 263篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 28篇 |
综合类 | 2篇 |
化学工业 | 1068篇 |
金属工艺 | 31篇 |
机械仪表 | 54篇 |
建筑科学 | 244篇 |
矿业工程 | 12篇 |
能源动力 | 84篇 |
轻工业 | 587篇 |
水利工程 | 50篇 |
石油天然气 | 10篇 |
无线电 | 238篇 |
一般工业技术 | 611篇 |
冶金工业 | 671篇 |
原子能技术 | 17篇 |
自动化技术 | 511篇 |
出版年
2024年 | 11篇 |
2023年 | 71篇 |
2022年 | 139篇 |
2021年 | 228篇 |
2020年 | 127篇 |
2019年 | 152篇 |
2018年 | 178篇 |
2017年 | 140篇 |
2016年 | 152篇 |
2015年 | 107篇 |
2014年 | 154篇 |
2013年 | 283篇 |
2012年 | 223篇 |
2011年 | 307篇 |
2010年 | 215篇 |
2009年 | 233篇 |
2008年 | 202篇 |
2007年 | 188篇 |
2006年 | 156篇 |
2005年 | 100篇 |
2004年 | 114篇 |
2003年 | 96篇 |
2002年 | 64篇 |
2001年 | 56篇 |
2000年 | 53篇 |
1999年 | 37篇 |
1998年 | 49篇 |
1997年 | 46篇 |
1996年 | 40篇 |
1995年 | 33篇 |
1994年 | 29篇 |
1993年 | 27篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 23篇 |
1989年 | 21篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1981年 | 7篇 |
1976年 | 6篇 |
1974年 | 5篇 |
1947年 | 8篇 |
1946年 | 5篇 |
1945年 | 6篇 |
1944年 | 11篇 |
1943年 | 7篇 |
1942年 | 10篇 |
排序方式: 共有4218条查询结果,搜索用时 0 毫秒
31.
Gemma M. Paech Sarah M. Jay Nicole Lamond Gregory D. Roach Sally A. Ferguson 《Applied ergonomics》2010,41(4):600-606
Shiftwork involving early morning starts and night work can affect both sleep and fatigue. This study aimed to assess the impact of different rostering schedules at an Australian mine site on sleep and subjective sleep quality. Participants worked one of four rosters;
- 4 × 4 (n = 14) 4D4O4N4O
- 7 × 4 (n = 10) 7D4O7N40
- 10 × 5 (n = 17) 5D5N50
- 14 × 7 (n = 12) 7D7N70
32.
The additive model of multiattribute value theory is widely used in multicriteria choice problems. But often it is not easy to obtain precise values for the scaling weights or the alternatives’ value in each function. Several decision rules which require weaker information, such as ordinal information, have been proposed to select an alternative under these circumstances. We propose new decision rules and test them using Monte-Carlo simulation, considering that there is ordinal information both on the scaling weights and on the alternatives’ values. Results show the new rules constitute a good approximation. We provide guidelines about how to use these rules in a context of selecting a subset of the most promising alternatives, considering the contradictory objectives of keeping a low number of alternatives yet not excluding the best one. 相似文献
33.
This small scale action research study investigated the experiences of learners over two iterations as they completed a patchwork text assignment within the digital medium of a personal learning system (PLS). The aim was to investigate the extent to which using a PLS can facilitate formative and collaborative feedback to assist student learning. A secondary question, linked to the course being a post graduate Certificate for new HE teachers within a geographically dispersed university, was to examine if using a PLS in the programme would influence their interest in using it with their own students in the future. This question is of particular importance for the tutors of this programme, as the university attracts mainly part-time students who are studying at a distance from the university campus. The study was carried out as part of the JISC funded Flourish Project, whose overall aim was to examine the use of a PLS to support the development of academic staff. 相似文献
34.
Many applications require teams of robots to cooperatively execute tasks. Among these domains are those in which successful
coordination must respect intra-path constraints, which are constraints that occur on the paths of agents and affect route
planning. This work focuses on multi-agent coordination for disaster response with intra-path precedence constraints, a compelling
application that is not well addressed by current coordination methods. In this domain a group of fire truck agents attempt
to address fires spread throughout a city in the wake of a large-scale disaster. The disaster has also caused many city roads
to be blocked by impassable debris, which can be cleared by bulldozer robots. A high-quality coordination solution must determine
not only a task allocation but also what routes the fire trucks should take given the intra-path precedence constraints and
which bulldozers should be assigned to clear debris along those routes. 相似文献
35.
Several Grids have been established and used for varying science applications during the last years. Most of these Grids, however, work in isolation and with different utilisation levels. Previous work has introduced an architecture and a mechanism to enable resource sharing amongst Grids. It has demonstrated that there can be benefits for a Grid to offload requests or provide spare resources to another Grid. In this work, we address the problem of resource provisioning to Grid applications in multiple-Grid environments. The provisioning is carried out based on availability information obtained from queueing-based resource management systems deployed at the provider sites which are the participants of the Grids. We evaluate the performance of different allocation policies. In contrast to existing work on load sharing across Grids, the policies described here take into account the local load of resource providers, imprecise availability information and the compensation of providers for the resources offered to the Grid. In addition, we evaluate these policies along with a mechanism that allows resource sharing amongst Grids. Experimental results obtained through simulation show that the mechanism and policies are effective in redirecting requests thus improving the applications’ average weighted response time. 相似文献
36.
Sarah Hamel 《国际通用系统杂志》2016,45(6):689-710
In this paper, a modified generalized function projective synchronization scheme for a class of master–slave chaotic systems subject to dynamic disturbances and input nonlinearities (dead-zone and sector nonlinearities) is investigated. This synchronization system can be seen as a generalization of many existing projective synchronization schemes (namely the function projective synchronization, the modified projective synchronization and so on), in the sense that the master system has a scaling function matrix and the slave system has a scaling factor matrix. To practically achieve this generalized function synchronization, an adaptive fuzzy variable-structure control system is designed. The fuzzy systems are used to appropriately approximate the uncertain nonlinear functions. A Lyapunov approach is employed to prove the boundedness of all signals of the closed-loop control system as well as the exponential convergence of the synchronization errors to an adjustable region. Simulations results are presented to illustrate the effectiveness of the proposed generalized function PS scheme. 相似文献
37.
NOAA Radios and Neighbourhood Networks: Demographic Factors for Channel Preference for Hurricane Evacuation Information 下载免费PDF全文
Sarah E. DeYoung Tricia Wachtendorf Ashley K. Farmer Samantha C. Penta 《突发事故与危机管理杂志》2016,24(4):275-285
This paper reviews literature on information channel type and disasters, and presents results on hurricane evacuation information gathering. Results show that respondents reported they would use television and radio most frequently for gathering information about hurricane evacuation. Minority respondents reported more preference of the use of community or local government as information sources than white respondents, females gathered information from multiple channels more than males, and younger residents gathered information from multiple channels more than older respondents. Implications include areas for future research in how channel utilization occurs during slow onset hazards in predominantly black communities, how age and gender relate to channel preference, and how channel preferences affect length of time to make decisions and engage in protective actions. 相似文献
38.
Muhammad Usman Muhammad Moazam Fraz Sarah A. Barman 《Archives of Computational Methods in Engineering》2017,24(3):449-465
The retina is a tiny layer at the posterior pole of an eye and is made up of tissues sensitive to light, these tissues generate nerve signals that pass through the optic nerve to the brain. A retinal disorder occurs when the retina malfunctions; glaucoma, diabetic retinopathy and pathologic myopia are retinal disorders and principal causes of blindness worldwide. These retinal disorders are often diagnosed and treated by an ophthalmologist. However, to accurately assess a retinal disease, ophthalmologist would need qualitative and quantitative analysis of the disease, it’s early and current statistics, but acquisition of these measurements are not possible through manual techniques, there should be automated computer aided diagnosis (CAD) systems to assist ophthalmologists. In this comprehensive review, an analysis and evaluation has been performed of different computer vision and image processing approaches applied to OCT images for automatic diagnosis of retinal disorders. We also reported disease causes, symptoms and pathologies manifestations within OCT images, which can serve as baseline knowledge for development of an automated CAD system. Hence, this disease specific review offers a good understanding to analyze visual impairments from retinal OCT images which will help researcher to design enhanced therapeutic systems for retinal disorders. 相似文献
39.
One of the recurring questions in designing dynamic control environments is whether providing more information leads to better operational decisions. The idea of having every piece of information is increasingly tempting (and in safety critical domains often mandatory) but has become a potential obstacle for designers and operators. The present research study examined this challenge of appropriate information design and usability within a railway control setting. A laboratory study was conducted to investigate the presentation of different levels of information (taken from data processing framework, Dadashi et al. in Ergonomics 57(3):387–402, 2014) and the association with, and potential prediction of, the performance of a human operator when completing a cognitively demanding problem-solving scenario within railways. Results indicated that presenting users only with information corresponding to their cognitive task, and in the absence of other, non task-relevant information, improves the performance of their problem-solving/alarm handling. Knowing the key features of interest to various agents (machine or human) and using the data processing framework to guide the optimal level of information required by each of these agents could potentially lead to safer and more usable designs. 相似文献
40.
Sarah Mostame Joonsuk Huh Christoph Kreisbeck Andrew J. Kerman Takatoshi Fujita Alexander Eisfeld Alán Aspuru-Guzik 《Quantum Information Processing》2017,16(2):44
With quantum computers being out of reach for now, quantum simulators are alternative devices for efficient and accurate simulation of problems that are challenging to tackle using conventional computers. Quantum simulators are classified into analog and digital, with the possibility of constructing “hybrid” simulators by combining both techniques. Here we focus on analog quantum simulators of open quantum systems and address the limit that they can beat classical computers. In particular, as an example, we discuss simulation of the chlorosome light-harvesting antenna from green sulfur bacteria with over 250 phonon modes coupled to each electronic state. Furthermore, we propose physical setups that can be used to reproduce the quantum dynamics of a standard and multiple-mode Holstein model. The proposed scheme is based on currently available technology of superconducting circuits consist of flux qubits and quantum oscillators. 相似文献